Heat exchanger bearing arrangement



Patented May 27, 1952 UNITED STATE TENT OFFICE HEAT EXCHANGER BEARINGARRANGEMENT Application December 6, 1948, Serial No. 63,757 In GreatBritain December 12, 1947 2 Claims. 1

This invention relates to heat exchangers of the rotary regenerativetype, that is to say of the type in which different parts of a rotarymatrix are simultaneously exposed to hot and cold fluid flows so that inthe course of its rotation the matrix receives heat from the one flowand imparts heat to the other. Such heat exchangers have particularapplication to gas turbine power plant and it is in such plant that aheat exchanger in accordance with the invention may be expected mainlyto be used.

In particular the invention relates to such heat exchangers of the drumtype in which the rotary matrix is of cylindrical form and the fluidflows are guided by casing structure to pass radially through thematrix, the drum being mounted at its end on the casing structure forrotation about its own axis. In that type of heat exchanger it isconvenient, in order to allow axial flow of fluid through the ends ofthe drum, to mount the drum in a peripheral bearing support, anarrangement which enhances the difficulty, already inherent in therotary regenerative type of exchanger, of dealing with the tendency ofthe bearings to overheat, and with problems arising from relativethermal expansion of different parts. An object of the present inventionis to provide an improved bearing arrangement and structure for heatexchangers of thedrum type referred to which will mitigate thesedifficulties.

Accordingly the invention proposes to provide a heat exchanger of therotary drum type referred to having an end supporting bearing of whichthe relatively moving bearing parts are axially spaced away from endstructure of the drum and of the stationary casing by which the boundaryof the fluid flow path is defined, and are respectively connected tosaid structures by axially extending annular supporting structuresarranged v some capacity for yielding in the radial direction toaccommodate thermal stress.

In the normal type of construction the heat exchanger casing willinclude structure both internally and externally of the drum, and insuch a case it is proposed, in further accordance with It is intendedthat said cross-section the invention, that the annularbearing-supporting structure associated with the casing should compriseradially spaced concentric walls united at their axially outer ends,between which walls at an intermediate radius and concentric therewithlies the annular bearing-supporting structure associated with the drum.A double-walled stationary annular supporting structure such as has justbeen described may be used to accommodate at one or more points aboutthe periphery of the bearing a pinion meshing with a gear ring on theannular supporting structure associated with the drum, which pinion maytransmit drive either to or from the drum or might be used for examplefor the distribution of oil. It will be noted also that the kind ofannular supporting structure envisaged will provide virtually an annularpocket in the casing with its open side presented to the rotor, whichcan be arranged substantially to close the pocket; in this way ampleprovision is made for either a convective or a forced cooling air flowif required. The outer annulus may further be provided internally withstructure forming in conjunction with the annulus associated with thedrum an enclosed or more or less enclosed annular channel serving atsome part of its circumference as an oil collecting chamber orreservoir.

An example of construction in accordance with the invention isillustrated in the accompanying drawings, in which Figure 1 illustratesdiagrammatically the general form of a drum type heat exchangerembodying the invention, and Figure 2 is an enlarged detail section ofthe bearing arrangement illustrated in Figure 1 (the view correspondingto the top right-hand corner of Figure 1).

Referring now to Figure 1 of the drawings, the heat exchanger comprisesa drum l rotatably mounted at each end on bearings 2 supported in acasing having inner and outer parts, 3, 3a which together define two gasflow paths 4, 5 intended for the flow of cold and hot gasesrespectively. It will be noted that each gas path includes regions ofradial flow through the wall of the drum and axial flow through the endsof the drum and easing, the wall of the drum I for this purpose beingmainly afforded by a matrix is which is permeable to the gas flows.Normally it will be arranged that the hot gas enters radially andemerges axially whilst the cold gas enters axially and emerges radiallyso that the variation of the flow path area will be in the sense as thevariation of gas volume with temperature.

The heat exchanger as so far described is broadly known and is merelyintended to typify the class of apparatus to which the invention hasparticular application; the invention itself is concerned with thebearing arrangement used. In the example illustrated, each bearing 2 isaxially spaced from the end of the main structure of the drum l and fromthe parts of the casing 3, 3a which define the boundary of the radialgas flow path. The stationary part 6 of the bearing structure isconnected to and supported on the inner casing part 3 by an annulus I ofreduced cross-section. The annulus 1 is also connected through anassociated end wall 8 and an outer annulus 9 concentric with the annulusI to the outer casing part 3a. The movable part 6a of the bearing, onthe other hand, is connected to and supported on the end wall of thedrum 1 by means of an annulus l0, also of reduced cross section, lyingconcentrically between the annuli I and 9.

The intention of this arrangement is primarily to restrict the heat flowfrom the hot parts of the casing and drum to the bearing and it also hasthe advantage of providing some capacity for radical yielding toaccommodate thermal stresses. annuli 1, 9, and end wall 8 form threesides of an annular chamber or pocket ll of substantial axial depth, theopen side of which is presented to the gas flow channel but accommodatesand is substantially closed by the end rim of the drum 1; the chamber llso provided offers ample provision for a convective or forced coolingair flow if that should be desirable or necessary. In addition, in thepreferred form of the invention illustrated in Figure 2, the chamber His used to accommodate at one or more positions around its circumferencea pinion such as 12 meshing with a gear ring [3 provided on the bearingpart 6a, which pinion may either drive or be driven by the gear ring l3.The structure also includes an angle section ring I4 forming with a ribMa on the annulus a substantially enclosed annular chamber which at itslower part acts as an oil reservoir: in which a loose pinion may bearranged in order positively to pick up oil and transfer it to the gearring 13 and thence to the bearing 2 in that region.

The walls 1, 9, by being made suitably thin, are able to accommodaterelative radial expansion as between the colder inner structure 3 andthe hotter outer structure 3a; in order to accommodate relative axialexpansion of these parts the inner wall I at one end of the apparatus issupported in an axially slidable manner on studs 15 on the structure 3.The wall I at the other end, of course, is securely attached to thestructure 3 so as to provide a fixed point from It will be noted alsothat the which axial expansion of the bearing structure I, 9, can takeplace.

I claim:

1. In a rotary drum type regenerative heat exchanger comprising incombination a hollow rotary drum with a fluid-permeable rim having asolid portion at one end, a casing enclosing said drum, and a ductportion on said casing defining a part extending radially up to saidpermeable rim, of a fluid path, which path continues through said riminto the interior of the drum and axially out from the drum, theprovision of inner and outer annular walls extending axially from saidcasing outwardly away from said fluid path concentrically with saiddrum, an end wall uniting the said inner and outer axially extendingwalls to form therewith an annular bearing chamber within said casingbut screened from the hot fluid path by said solid end portion of therim of the drum, a thin third annular wall extending axially from saidsolid end portion of said rim away from said fluid path andconcentrically into said bearing chamber, a bearing for the drum mountedwithin said chambgr between said inner annular wall and said thirdannular wall at the outer end of the latter, remote from the hot gaspath, and an axial duct portion on said casing extending inside butspaced from said inner wall to define said axial part of the fluid pathfrom the interior of the drum, thus shielding the inner andbearing-carrying wall from the hot fluid path.

2. A rotary heat exchanger according to claim 1 with driving gear forsaid rotary drum comprising a toothed gear rim formed around saidannular wall extending from the rim of the drum and a driving pinionhoused Within said bearing-chamber and meshing with said toothed gearrim.

PAUL KOLB.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,516,108 Ljungstrom Nov. 18,1924 1,939,153 Villasuso Dec. 12, 1933 2,055,071 Eriksson Sept. 22, 19362,313,084 Manly Mar. 9, 1943 2,364,951 Corte Dec. 12, 1944 2,413,567Hornbostel Dec. 31, 1946 FOREIGN PATENTS Number Country Date 620,602Great Britain Mar. 28, 194:9 78,254 Sweden Apr. 26, 1932

